Investment Securities (Narrative) (Details) - USD ($)	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Investment [Line Items]
Fair value of investments reported at less than historical cost	$ 142,900,000	$ 143,800,000
Percentage of Bank portfolio	51.50%	57.60%
Held to maturity, securities	$ 0	$ 0
Securities pledged as collateral	0	0
Proceeds from sales of securities, available for sale	34,592,000	57,037,000	$ 23,109,000
Gross realized gain on sale of securities	776,000	1,100,000	436,000
Gross realized losses on sale of securities	$ 68,000	$ 71,000	$ 0
Banks, thrifts or other depository institutions to all projected defaults
Investment [Line Items]
Collateral recovery probability percentage	10.00%
Insurance Companies to all projected insurance defaults
Investment [Line Items]
Collateral recovery probability percentage	15.00%

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Percentage of expected recoveries to remaining performing collateral

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Percentage Of Total Investment Portfolio In Unrealized Loss Position Fair Value

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This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities.

+ References

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-Publisher FASB
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This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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The fair value of available-for-sale securities that serve as collateral for borrowings.

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Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

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The cash inflow associated with the sale of debt and equity securities classified as available-for-sale securities.

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